Curcumin-Based 'Enhanced SNAr' Promoted Ultrafast Fluorescent Probe for Thiophenols Detection in Aqueous Solution and in Living Cells

We report herein a highly selective and sensitive turn-on fluorescent probe (compound 1) with a fast response time (less than 2 min) for thiophenol detection based on an enhanced SNAr reaction between thiophenols and a sulfonyl-ester moiety covalently attach to curcumin. Reaction of 1 in Hepes-MeOH (1:1, v/v, pH 7.4) in the presence of 4-methylthiophenol (MTP) resulted in a remarkable enhancement of the fluorescence. A linear response in the presence of MTP of the relative fluorescent intensity (F - F0) of 1 at 536 nm in the 0-40 mu M MTP concentration range was found. A limit of detection (LOD) for the detection of MTP of 26 nM, based on the definition by IUPAC (C-DL = 3 Sb/m), was calculated. Probe 1 was applied to monitor and imaging exogenous MTP in live cells and to the detection of MTP in real water samples.
The work was supported by the National Natural Science Foundation of China (Grant No. 21472118, 21672131), the Program for the Top Young and Middle-Aged Innovative Talents of Higher Learning Institutions of Shanxi (TYMIT, Grant No. 2013802), Talents Support Program of Shanxi Province (Grant No. 2014401), Shanxi Province Outstanding Youth Fund (Grant No. 2014021002), Scientific Instrument Center, Shanxi University and Shanxi University funds for study aboard 2014. The Generalitat Valenciana (Project PROMETEOII/2014/047) and the Spanish Government (Projects MAT2012-38429-C04 and MAT2015-64139-C4-1 MINECO/FEDER)) are also gratefully acknowledged.